Electric switch



W. A. GUSSOW ELECTRIC SWITCH Jan. 15, 1952 2 SHEETS-SHEET 1 Filed Aug.21, 1950 W/l/iam A 6 u 680 w IN V EN TOR.

w. A. GUSSOW ELECTRIC SWITCH 2 SHEETSSHEET 2 William A. Gussow INVENTOR.

Jan. 15, 1952 Filed Aug.- 21, 1950 Patented Jan. 15, 1952 ELECTRICswrron William A. Gussow, Hampton, Ga., assignor to Southern StatesEquipment Corporation, a corporation of Georgia Application August 21,1950, Serial No. 180,563

I This invention relates to high voltage electric switches, andparticularly to counterbalancing a pivotally mounted switch arm which ismovable from its open to its closed position. To counterbalance the armsof both vertically mounted and upright mounted switches, springs can bedirectly applied. But this cannot be done effectively on underhungswitches.

One purpose of this invention is to produce a switch arm correctlycounterbalanced for underhung mounting; another purpose is to produce insuch a mechanism a counterbalancing device which does not interfere withthe members which operate the switch, which is readily applied orremoved, which is compact, which can be assembled Without having anystrain on the spring or springs, which can readily be tensed afterassembly, and which can easily be adjusted or modified after trial.

Referring to the drawings, Figure 1 shows in small scale an underhungswitch which includes this invention; Figure 2 is a larger scalesectional view on line 22 in Figure 6, Figure 3 is a similar view online 3-3 in Figure 6, and these show how the two ends of one of thecounterbalancing springs are held; Figure 4 is a chart diagrammaticallyshowing the principles of operation; Figure 5 shows in large scale aside view of the counterbalancing mechanism; and Figure 6 in the samescale shows a view on the line 66 in Figure 5, but with some memberssectionized at two locations.

Condiitons in an underhung switch are radically different fromconditions when a similar switch is mounted in a vertical or in anupright position, as shown in Figure 4. Referring to this chart, 8represents the hinge pivot about which the switch arm Trotates. From thehorizontal position H, the arm moves upwardly in direction U to positionU, or it moves from position H downwardly in direction D to position D.In an upright switch H is the closed position and U the open position;in a vertical switch H is the open position and U is the closedposition; and in an underhung switch H is the closed position and D isthe open position.

On all large switches the force of gravity is considerable and theswitch arm has to be counterbalanced; the rotative effect of gravity isgreatest at position H and it is least at position U or D. When theswitch arm travels from H to U, a counterbalancing spring can beconnected directly to the arm and stressed to bias the arm upwardlyagainst the force of gravity. As the arm moves in direction U it ismoving in the 6 Claims. (Cl. 200-48) direction of the bias caused by thespring, and so the stress of the spring relaxes. Also the rotativeefiect of gravity becomes continuously lessened as the arm approachesposition U. It is relatively simple to coordinate these two forcesclosely enough to make the switch operable manually.

But on an underhung switch the motion of the arm from H in direction Dis with gravity, not against it, and therefore as the arm makes thismotion it is moving against the bias of the counterbalancing spring, notwith it. And any motion against the bias of the spring tends to increasethe pressure developed by the spring. Therefore, to counterbalance anunderhung switch arm correctly the spring mechanism must produce maximumrotative bias at H, and then as the arm moves from H towards D therotative effect must be continuously reduced, even though this motion isagainst the bias caused by the spring. This invention meets theserequirements.

Referring to the drawings, the support I carries two stationaryinsulators 2, 3 and one rotatable insulator 4;' the base 5 is bolted toinsulator 3 and it is movably secured to insulator 4 by pivotal bearing6 which allows insulator 4 to rotate. .The switch arm I is pivotallymounted on base 5 by the long hinge pivot 8. The switch arm assembly 1includes the long extension which engages with the jaw contact 9, andalso the associated members which rotate with this long extension aboutthe same axis. Jaw contact 9 is secured to insulator 2. Crank H is fixedto insulator A and rotates with it. Link I2 connects crank H with therear extension of switch arm 1. Rotation of insualtor 4 thereby operatesthe switch as explained in Patent No. 2,520,036. i Crank I3 is securedby key l3 to the end of hinge pivot 8, and switch arm assembly I issecured to hinge pivot 8 by key 8, therefore switch arm I and switchcrank l3 rotate together with hinge pivot 8. In the end of crank 13 isthe pivot pin I4", which is thus held in fixed relation to switch arm Iand rotates with switch arm I about the axis of switch pivot 8. Rod I4is pivotally held at one end by pivot pin 14'', and at the other endrod, I 4 is pivotally connected to spring crank [5. These parts move asshown in Figure 4 from closed positions A and B to open positions A andB which are shown by dotted lines. Similar members, opposite hand,marked [3, l4' and [5, are on the other side of the switch. Crank I5 issecured by key IE to spring pivot l1. Bolts I8I8 hold crank I5 to collar19 which makes a slip fit over spring pivot I1,

while radial corrugations 20-20 and slots 2 l-2! allow non-slippingadjustments to be made between crank I5 and collar I9. A long coilspring 22 engages with projections 23, 24 on collar I9, as shown inFigure 2. Housing 25 surrounds spring 22, and projections 26, 26 engagethe inner end of spring22 as shown in Figure 3-. The other end ofhousing 25surrounds a similar spring 22', and all members on the twosides of the switch are similar but opposite hand. The two springs. '22and 22 act similarly to counterbalance switch arm 'I, each doing half ofthe work.

Lug 21 and a similar lug. on the opposite side of the switch areintegral with housing 25 which is thus rigidly secured by bolts 28-28 tobase 5. Inside housing 25 two conic-a1 sleeves 29, 29 provide two spacedbearings 30, 30 which'support spring pivot H and allow it to rotate.

Collars l9 and I9 have short radially disposed slots 3l-3I into. whicha. bar may be inserted to turn collar I9 or IS. The spring 22, beingheldatthe ends as shown inFigures 2 and. 3, has its entire centralportion. freev to. contract and expand as stress is increased. orreduced. In. as.- sembling, all parts. are put. together without anystress being applied to springs 22, 22'. Then with bolts [8-48 loosenedor removed and a bar inserted in a. slot 31, collar I9. is turned untilthe desired stress is developed in spring 22. -B0lts I8 --I-8 are thentightened, and a similar adjust- .1

ment is made at collar I9, so that springs 22 and 22" together biasswitch arm I upwardly towards positionH; See Figure 4.

When at position H, arm I3 is at the position A; and arm I5 is at theposition B, thereby forming. with rod I4-a very obtuse angle. Meanwhilecrank I3 and rod l4 form an angle that is. close to 90. In thesepositions, the rotative effect on switch arm I is stronger than thedirect rotative effect of spring. 22. As switch arm T is lowered indirection D the angles formed by rod I4 with cranks I 3 and I5 changecontinuously; and when switch. arm I has reached the fully open positionat D, the crank I3 is at position A and forms an obtuse angle with rodl4, while crank l5 at position B forms-a right angle, approximately,with rod I4. And. in these positions the torsional bias on switch arm "Iis. much less than the torsional effect directly exerted by spring 22against crank l5.

Springs 22, 22' are quite long and they are operated over only a smallpart of their elastic range, and the changes in the torque exerted byeach spring is much less than the changes in leverage developed betweenthe spring cranks, the rods and the switch cranks. Therefore when allmembers are properly proportioned, springs 22, 22' will exert maximumtorque on switch arm I when at its horizontal position H, and a minimumtorque when switch arm I is at its open position D, even though thetorque exerted by springs 22 and 22 against collars I9 and I9 is justthe opposite. These results are achieved by a combination of severalfeatures.

In assembling, the switch itself is put together and adjusted, withhousing 25 and rods I4, I l omitted. Then lug. 2.1 and the similar lugon the other side of housing 25 are rigidly bolted to base. 5, base 5also provides the journals in which hinge pivot 8 rotates. Therebyspring. pivot I1. is held in fixed relation to hinge pivot 3. and allstresses due to. tension on springs 22, 22' are contained. by base 5.Housing 25 being entirely below base 5 does not interfere in any waywith operation of the switch. After complete assembly, springs 22, 22are stressed to the proper tension as described above, and all tensiondeveloped between pivots 8 and I1 is absorbed by base 5, withoutimposing any undesirable strains on any of the insulators. And if itshould be desired to change the total counterbalancing effect. ofsprings 22, 22' then bolts I8I8-can be loosened enough to allowcorrugations 2G20 to slip past one another as collar I9; is rotated thedesired amount, by means of a bar inserted in one of the slots 3|. Thenbolts |8I 8 are tightened again.

The inner ends of springs 22, 22' are close together, and the outer endsare close to cranks I5,v I:5-' thereby housing two long lengths ofspring Wire in a compact space. But having sleeves 29, 29 and bearings38, 39 located inside the coiled springs, gives a wide spacing betweenbearings 38, 39 and supports pivot I? close to collars IS, IS, which iswhere the stress of the springs is applied. This makes possible a verycompact unit.

The hinge pivot assembly is alsocompact. The pivot 3' is journalled attwo places by base. 5, and between these journals the switch armassembly l is keyed to pivot 8 by key 8, while crank I3 is also keyed topivot 8 by key I3". Thus the only torsion imposed on pivot 8 is betweenkeys I3 and 8'. A similar arrangement is. provided at the other end ofpivot 8..

The combination of the two cranks I3, I3 on the ends of pivot 8, twocranks l5, I5 on the ends of pivot I which are stressed by two springs22, 22, and two rods, I4, M connecting the pairs of cranks together,form a complete and compact counterbalancing unit which is mostefficient. In actual service it has been found that the device as heredisclosed makes easy the manual operation of underhung three-poleswitches of even the largest sizes.

I claim:

1. In an electric switch, a hinge pivot, a switch arm rotatable about.the axis of the hinge pivot from a position that. is approximatelyhorizontal downwardly to a position more nearly vertical,

a base which supports the hinge pivot and which also supports a springpivot which is parallel with and spaced from the hinge. pivot, a switchcrank connected with the switch arm and rotatable with the switch armabout the axis of the hinge pivot, a spring crank rotatable about theaxis of the spring pivot, a spring connected with the spring crank tobias it rotatively, a rod pivotally connected at its two ends,respectively, with the swing ends of the two said cranks, the rod andthe switch crank defining an angle that is approximately a right anglewhen the switch arm is horizontal and that is an obtuse angle when theswitch arm is more nearly vertical, and the rod and the spring crankdefining an angle that is obtuse when the switch arm is horizontal andthat is approximately a right angle when the switch arm is more nearlyvertical; the said spring and its associated members thereby acting tocounterbalance at least partially the switch arm.

2. In an electric switch similar to that described in claim 1, a switchcrank on each end of the hinge pivot, a spring crank on each end of thespring pivot, two rods each of which pivotally connects together oneswitch crank with one spring crank, and two springs which bias the twospring cranks, and thereby act together to counterbalance the switch armin a manner similar to that described in claim 1.

3. In an electric switch, a hinge pivot, a switch arm rotatable aboutthe axis of the hinge pivot, a pair of pivot pins fixedly held one ateach side of the switch arm to rotate with the switch arm about the axisof the hinge pivot; and fixedly spaced from the hinge pivot a switch armcounterbalancing mechanism which includes a spring pivot parallel withthe hinge pivot, two spring cranks one at each end of the spring pivotand rotatable together about the axis of the spring pivot, and springmeans to bias the two spring cranks rotatively in the same direction;and two rods each one pivotally connected at one end to one of pivotpins and pivotally connected, respectively, at the other end to thecorresponding spring crank, whereby the spring means at least partlycounterbalances the switch arm.

4. In an electric switch, a hinge pivot, a switch arm rotatable aboutthe axis of the hinge pivot from a horizontal position downwardly to aposition more nearly vertical, a pivot pin fixedly connected with theswitch arm and rotatable with the switch arm about the axis of the hingepivot, a spring pivot fixedly located in spaced relation to the switchpivot and parallel with it, a spring crank rotatable about the axis ofthe spring pivot, a rod pivotally connected at one end to the said pivotpin and at its other end pivotally connected to the swing end of thespring crank, the said rod defining with the spring crank an angle thatis obtuse when the switch arm is in horizontal position and that is morenearly a right angle when the switch arm is more nearly vertical,together with a spring to bias the spring crank rotatively and therebyat least partly counterbalance the effect of gravity upon the switcharm.

5. In an electric switch, a hinge pivot, a switch arm rotatable aboutthe hinge pivot, and connected with the switcharm a counterbalancingmechanism which comprises a pair of spaced bearings supporting a springpivot that is fixedly spaced from and parallel with the hinge pivot, ateach end or the spring pivot a spring crank that is rotatable about theaxis of the spring pivot, two coil springs each surrounding one of thesaid spaced bearings, the inner ends of the springs being fixedly heldclose to one another, and the outer end of each spring being connectedwith one of the spring cranks in a manner to bias both spring cranks inthe same direction, and connecting means between the spring cranks andthe switch arm whereby the two springs at least partially counterbalancethe switch arm against gravity.

6. In an electric switch, a hinge pivot, a switch arm rotatable aboutthe hinge pivot, and connected with the switch arm a counterbalancingdevice which comprises a housing held in fixed spaced relation to theswitch pivot, two coil springs recessed, respectively, into each end ofthe housing and with the two inner ends of the springs close to oneanother and held against turning, two spaced bearings integral with thehousing and each bearing being located inside the coil of one of saidsprings, a spring pivot within the said bearings, a collar on the springpivot near each end of the spring pivot and engaged with the outer endof the coil spring, a spring crank on each end of the spring pivot, andadjustable means for connecting together each spring crank and theadjacent collar, together with means connecting each spring crank withthe switch arm whereby the two springs act together to counterbalancethe switch arm.

WILLIAM A. GUSSOW.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

